Put half the raspberries in a bowl with 1 tablespoon sugar. Mash with a fork.
Whip the cream with the powdered sugar until stiff peaks form (do not over-whip the cream).
With a slotted spoon, spoon the mashed raspberries into the whipped cream (discard the raspberry juices) and lightly fold the raspberries into the cream leaving it streaky.
Spoon half of the whipped cream/raspberry mixture into 4 small dessert bowls. Top with half the whole raspberries, the remaining cream, and the remaining raspberries. Garnish with chopped pistachios and mint leaves if desired.